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Narrator: When you're trying to detect a wavelength of light that our eyes can't see, like infrared
light, you need to use a detector that can tell you that it's there. The simple
circuit we're building here can receive a signal in infrared light and convert into sound.
You'll need a photocell or solarcell with two wire leads,
and audio cable with a headphone jack on one end and
wire leads on the other, two test leads with jumper clips at each end,
and an amplifier/speaker.
We'll star with the photocell. Gently attach one of the jumper
clips onto each of the wires coming from the photocell.
Now do the same with the wires on the audio cable,
clipping the other ends of the leads onto each one. It doesn't
matter which wire you clip each one onto as long as you've made a complete circle.
Now plug the other end of the audio cable into the jack marked
input on the amplifier/speaker. That's it, you've built a circuit that
receives the infrared signal from a source--such as a remote control--and sends
that signal to the amplifier/speaker which turns it into sound.
Music